Archives par mot-clé : Northern Hemisphere


by Maja Sojtaric, June 27, 2017

The Eurasian ice sheet was an enormous conveyor of ice that covered most of northern Europe some 23,000 years ago. Its extent was such that one could have skied 4,500 km continuously across it – from the far southwestern isles in Britain to Franz Josef Land in the Siberian Arctic. Suffice to say its existence had a massive and extremely hostile impact on Europe at the time.

This ice sheet alone lowered global sea-level by over 20 meters. As it melted and collapsed, it caused severe flooding across the continent, led to dramatic sea-level rise, and diverted mega-rivers that raged on the continent. A new model, investigating the retreat of this ice sheet and its many impacts has just been published in Quaternary Science Reviews.

Lowest Solar Activity In 200 Years Accompanied By High Northern Hemispheric Snow And Ice

by P. Gosselin from F. Bosse and F. Vahrenholt, June 18, 2017

In May the sun was very quiet as sunspot number was a mere 18.8, which is only 36% of what is typical for the month this far into the cycle. Seven days saw no sunspot activity at all.

The following chart shows the current cycle, Solar Cycle 24 (red), compared to the mean of the previous cycles (blue) and the similarly behaving SC 5 (black).

It’s clear that the current cycle is significantly weaker than the mean and far weaker than the cycles we saw throughout most of the warming 20th century.

New Paper: Northern Hemisphere Temperatures Rose 4–5°C Within ‘A Few Decades’ 14,700 Years Ago

By Kenneth Richard , April 2017

According to a new paper, the Bølling Warming event 14,700 years ago raised the surface temperature for the entire Northern Hemisphere by 4 to 5°C within a few decades.  This is a hemispheric warming rate of approximately 2.0°C per decade, which is 40 times faster than the 0.05 °C per decade global warming rate since 1850 (and 1998).

Atlantique Nord : le risque d’un refroidissement rapide au XXIe siècle revu à la hausse

par D. Swingedouw et al., CNRS, 15 février 2017

Dans le cadre du projet européen EMBRACE, une équipe d’océanographes a réexaminé ces 40 projections climatiques en se focalisant sur un point névralgique au nord-ouest de l’Atlantique Nord : la mer du Labrador. Cette mer est le siège d’un phénomène de convection, qui nourrit à plus grande échelle la circulation océanique de retournement. Ses eaux de surface se refroidissent fortement en hiver, deviennent plus denses que les eaux de profondeur et plongent vers le fond. La chaleur des eaux profondes est transférée vers la surface et empêche la formation de banquise